Conventionally, there has been known an etching process for processing patterns on a substrate by supplying an etchant onto the substrate such as a semiconductor wafer (see Japanese Laid-open Patent Publication No. 2010-177652). After the etching process, a rinsing process for replacing the etchant remaining on the substrate with rinse liquid is performed by supplying the rinse liquid onto the substrate.
However, it is hard to replace the etchant penetrating deeply into gaps between the patterns with the rinse liquid, and thus it needs time to complete the replacement in the gaps compared with the upper portions of the patterns. For this reason, there is a possibility that the lower portions of the patterns are excessively etched compared with the upper portions of the patterns. In other words, there is a possibility that an amount of etching of the patterns becomes uneven in a vertical direction.